The present invention relates to catalysts for polymerization of .alpha.-olefin, a process for producing .alpha.-olefin polymers, novel transition metal compounds and catalyst components for polymerization of .alpha.-olefin.
As catalysts for polymerization of .alpha.-olefin, those comprising metallocene and aluminoxane have been proposed (Japanese Patent Application Laid-open (KOKAI) No. 60-35007, Japanese Patent Publication (KOKOKU) No. 4-12283, etc.). However, since the afore-mentioned catalysts are soluble in reaction solvent, the obtained polymer has extremely poor properties in which the polymer has irregular particle shape, has low bulk density and includes a large amount of fine powder therein. Therefore, in the case where these catalysts are applied to a slurry polymerization or a gas-phase polymerization of .alpha.-olefin, there have been caused various problems concerning the production of polymers, for example, it has been difficult to conduct safe operations continuously, for the production of polymers.
On the other hand, in order to solve the afore-mentioned problems, there have been proposed catalysts obtained by supporting one or both of a transition metal compound and an organoaluminum on an inorganic oxide such as silica or alumina or an organic substance (Japanese Patent Applications Laid-Open (KOKAI) Nos. 61-108610, 60-135408, 61-296008, 3-74412 and 3-74415, etc.).
However, polymers obtained by using such catalysts have contained a large amount of fine particles or coarse particles, and deteriorated in particle properties such as low bulk density. Further, there arises problems in which the catalysts have a low catalytic activity for the polymerization based on unit weight of solid components thereof, and the obtained polymers have disadvantages such as lower molecular weight or lower stereo regularity as compared to those obtained by using catalysts not supported on a carrier.